1. Field of the invention
The invention relates to a fuel reserving device.
2. Description of the Related Art
Before fuel is fed to a tank for holding fuel, a cap for closing an inlet of the fuel tank is removed therefrom. When the cap is removed, fuel vapor may be discharged from the fuel tank to the atmosphere via the inlet.
In order to avoid discharging the fuel vapor, Japanese Unexamined Patent Publication No. 8-121279 discloses a device for preventing fuel vapor from being discharged from a fuel tank to the atmosphere. The device comprises a reservoir connected to the fuel tank via a pipe and a compressor arranged in the pipe. In order to avoid discharging the fuel vapor from the fuel tank to the atmosphere, when the pressure in the fuel tank is higher than a predetermined pressure before the fuel is fed to the fuel tank, the compressor is activated to feed the fuel vapor from the fuel tank to the reservoir to decrease the pressure in the fuel tank. Then the fuel is fed to the fuel tank.
Further, in the above device, the reservoir communicates with the fuel tank after the feeding of the fuel is completed. The pressure in the reservoir is relatively high since the fuel vapor is fed from the fuel tank to the reservoir by the compressor. Therefore, the pressure in the fuel tank becomes relatively high after the reservoir communicates with the fuel tank. Thus, the fuel tank needs a relatively high durability to withstand the high pressure and this leads to high manufacturing costs.
Therefore, the object of the invention is to provide a fuel reserving device which prevents fuel vapor from being discharged therefrom to the atmosphere while the device needs a relatively low durability.